► The present work deals with the preparation of ruthenium nanoparticles using an organometallic approach. In the first part, the synthesis of ruthenium nanoparticles stabilized…
(more)

▼ The present work deals with the preparation
of ruthenium nanoparticles using an organometallic approach. In the
first part, the synthesis of ruthenium nanoparticles stabilized by
mesogenic isonicotinic ester ligands is presented. We have been
interested in the use of long-chain isonicotinic esters as
lipohilic components in order to increase the anticancer activity
of arene ruthenium complexes, while using them as stabilizers for
ruthenium nanoparticles with the aim of exploring self-organization
and biological (anticancer) properties of these new hybrid
materials. The ruthenium nanoparticles thus obtained as well as
their organometallic precursors showed anticancer activity
comparable to cisplatin or superior to cisplatin in the cancer cell
lines A2780 and cisplatin-resistant cell line A2780cisR, the
highest cytotoxicity being 0.179 µM, a value 9 fold lower than
cisplatin – a platinum-based chemotherapy drug widely used to treat
different types of cancers. In second part,
silicate-supported ruthenium nanoparticles with a special emphasis
on hectorite-supported Ru(0) is presented. Size- and
shape-selective preparation of hectorite-supported ruthenium
nanoparticles was achieved by using either molecular hydrogen or
solvothermal reduction route employing different organometallic
precursors. The catalytic efficiency of these nanoparticles was
evaluated for different arenes, furfuryl alcohol and
α,β-unsaturated ketones. Hectorite-supported ruthenium
nanoparticles were found to be promising hydrogenation catalysts.
It was observed that the modification of intercalated particles
size and reaction conditions tune the catalytic activity for
chemo-selective reactions. Thus, these nanoparticles preferentially
reduce the C=C olefinic bond in α,β-unsaturated ketones at 35 °C.
However, change in particle size results in high selectivity
towards C=O bond of α,β-unsaturated ketones, if an excess of
solvent is used at low temperatures. A selectivity > 98 % for an
unconstrained α,β-unsaturated ketone,
<i>trans</i>-4-phenyl-3-penten-2-one, was observed at 0
°C. This kind of selectivity is unique for a heterogeneous catalyst
especially when the C=C olefinic bond in α, β-unsaturated moiety is
sterically not hindered. It was believed that such a preferential
C=O bond hydrogenation in α,β-unsaturated ketones was not possible
with heterogeneous catalysts. In the last
part, superparamagnetic core-shell-type
Fe3O4/Ru
nanoparticles (particle size ~ 15 nm), synthesized by
co-precipitation, adsorption and reduction methods, are presented.
Their catalytic efficiency for selective C=O hydrogenation in an
unconstrained α,β-unsaturated ketone was evaluated using
<>trans</i>-4-phenyl-3-penten-2-one. These particles
present a green and sustainable approach towards catalyst
separation from the reaction mixture, as they can be efficiently
separated from the reaction mixture by applying an external
magnetic field. It was the aim of this study
to develop metallic ruthenium nanoparticles stabilized by…
Advisors/Committee Members: Georg (Dir.).

► N-Heterocyclic carbene and phosphorus ligands have been synthesized and used for many catalytic reactions including chiral analogs of Crabtree???s catalyst for asymmetric hydrogenation. These catalysts…
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▼ N-Heterocyclic carbene and phosphorus ligands have been synthesized and used for many catalytic reactions including chiral analogs of Crabtree???s catalyst for asymmetric hydrogenation. These catalysts have been studied extensively, especially on hydrogenation of "largely unfunctionalized" alkenes, for more than a decade. These substrates, however, could not be easily modified leading to limited applications for organic synthesis. As a result, asymmetric hydrogenations of substrates that have non- coordinating functional groups have gained more attention because the products are chirons that could be used to synthesize many natural products.
Even though many chiral analogs of Crabtree???s catalysts have been studied, none of these catalysts is perfect. Different catalysts could be suitable for different substrates. This point motivated us to investigate asymmetric hydrogenation of different substrates using our N,carbene Crabtree???s catalyst analog; for example, ??-methyl-??-alkyl-??-amino acid derivatives can be obtained with high stereoselectivities. Moreover, the same point also inspired us to synthesize the new N-heterocyclic carbene ligands to compare the effect on different catalysts that have related structure.
Design new ligands to obtain effective catalysts, however, needs high experience and it is possible time consuming with unpredictable outcomes. Using the screening method with mono-chelating phosphorus ligands synthesized from cheap and easily obtained starting materials might be possible solution. However, we cannot rule out the possibility that bi-chelating ligand of the related structure might give better selectivities. Cross metathesis is an easy method that can link two parts together to convert mono- chelating ligand to bi-chelating one. Using metathesis combined with catalysis ???metacatalysis??? is one method to compare catalytic activity of mono- and bi-dentate ligands. However, the result indicated that most this method was suitable in some cases but not all.
Advisors/Committee Members: Burgess, Kevin (advisor).

Sikdar, S. K. (1971). The effect of an electric field on the hydrogenation of ethylene on zinc oxide
. (Masters Thesis). University of Arizona. Retrieved from http://hdl.handle.net/10150/318141

Chicago Manual of Style (16th Edition):

Sikdar, Subhas K. “The effect of an electric field on the hydrogenation of ethylene on zinc oxide
.” 1971. Masters Thesis, University of Arizona. Accessed March 21, 2019.
http://hdl.handle.net/10150/318141.

MLA Handbook (7th Edition):

Sikdar, Subhas K. “The effect of an electric field on the hydrogenation of ethylene on zinc oxide
.” 1971. Web. 21 Mar 2019.

Vancouver:

Sikdar SK. The effect of an electric field on the hydrogenation of ethylene on zinc oxide
. [Internet] [Masters thesis]. University of Arizona; 1971. [cited 2019 Mar 21].
Available from: http://hdl.handle.net/10150/318141.

Council of Science Editors:

Sikdar SK. The effect of an electric field on the hydrogenation of ethylene on zinc oxide
. [Masters Thesis]. University of Arizona; 1971. Available from: http://hdl.handle.net/10150/318141

▼ This thesis describes the results from in situ catalytic rhodium(I) systems with acylated methionine sulphoxide ligands for the transfer hydrogenation of aryl alkyl ketones (eq. 1) and imines (eq. 2) from 2-propanol. All the chiral ligands studied are easily prepared derivatives of the amino acid methionine and include: N-acetyl-(S)-methionine-(R,S)-sulphoxide [(S)-AMSO], N-acetyl-(R)-methionine-(R,S)-sulphoxide [(R)-AMSO], and N-benzoyl-(S)-methionine-(R,S)-sulphoxide [(S)-BMSO].
[equation 1 omitted]
[equation 2 omitted]
The catalytic results for the transfer hydrogenation of acetophenone by (S)-AMSO with [RhCl(1,5-hexadiene)]₂ as the rhodium(I) precursor are, conversion = 26% and e.e. = 30% of the (R)-(+)-1-phenylethanol. The analogous system with (R)-AMSO as the chiral ligand gave approximately the same chemical and optical yields. However, when the ligand is (R)-AMSO, the (S)-(-)-alcohol is produced in excess, as opposed to the R enantiomer. A system with [RhCl(1,5-cyclooctadiene)]₂ added as the catalyst precursor gave, with either (S)- or (R)-AMSO as the chiral ligand, similar results for the optical yield (31-32%), but gave a somewhat larger chemical yield (34-36%) of 1-phenylethanol. With propiophenone as the substrate, the [RhCl(1,5-hexadiene)]₂/ (S)-AMSO system gave a 21% yield of 1-phenyl-l-propanol with 35% e.e. of the (R)-(+)-alcohol. (S)-BMSO was less successful as a ligand under the catalytic conditions used in these studies, giving both low chemical and optical yields with [RhCl(1,5-hexadiene)]₂ (10% and 13%, respectively). Use of this ligand with [RhCl(1,5-cyclooctadiene)]₂ gave more reasonable chemical yields (29%), but no enantiomeric excess was observed in the product. All the catalytic reactions required the addition of KOH as a cocatalyst for the successful transfer of hydrogen from 2-propanol. The reverse reaction, where 1-phenylethanol acts as the hydrogen donor, and acetone as the hydrogen acceptor (or substrate), was also shown to be catalysed by these rhodium(I)-AMSO in situ systems. The chemical yield of acetophenone produced by transfer of hydrogen from racemic 1-phenylethanol to acetone was 15%. However, no e.e. was observed in the remaining 1-phenylethanol, showing it was not enantioselectively dehydrogenated.
This in situ rhodium-(5)-AMSO system also catalysed the transfer hydrogenation of the imine N-benzylideneaniline to N-phenylbenzylamine in 80% yield. However, two prochiral imines N-(1-methylbenzyhdene)benzylamine and N-(1-methoxy-2-propylidene)2,6-dimethyl-aniline were not reduced under similar catalytic conditions; KOH was also added as a cocatalyst in these systems.
Several attempts at preparing coordination compounds of the ligands AMSO and BMSO proved unsuccessful. Further preparations of coordination compounds were not pursued in favour of concentrating on the more successful transfer hydrogenation studies involving these chiral ligands.
[equation 1 omitted]
[equation 2 omitted]
The…

Note: this citation may be lacking information needed for this citation format:Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Macfarlane KS. Asymmetric transfer hydrogenation using a rhodium(I) IN SITU system containing Chiral Sulphoxide Ligands
. [Thesis]. University of British Columbia; 1989. Available from: http://hdl.handle.net/2429/29471

Note: this citation may be lacking information needed for this citation format:Not specified: Masters Thesis or Doctoral Dissertation

► The development of more efficient carbon-carbon bond transformation is of great significance. One of the more common approaches to forging carbon-carbon bonds is the addition…
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▼ The development of more efficient carbon-carbon bond transformation is of great significance. One of the more common approaches to forging carbon-carbon bonds is the addition of carbon- based nucleophiles to carbonyl compounds, exploiting classical electrophile-nucleophile pairing. In an effort to minimize nucleophile pre-activation and organometallic byproducts, my research in the Krische group focuses on the development of efficient methods for the in-situ formation of alkyl-metal nucleophiles from π- unsaturated compounds via transition metal catalysis. With the use of Ruthenium or Osmium we can use readily abundant a-olefins such as ethylene gas and couple it with various secondary alcohols via transfer hydrogenative C-C coupling in a proposed oxidative coupling pathway.
Advisors/Committee Members: Krische, Michael J. (advisor), Martin, Stephen F (committee member), Anslyn, Eric V (committee member), Liu, Hung-Wen (committee member).

► The chemical building blocks that comprise petroleum asphaltenes were determined by cracking samples under conditions that minimized alterations to aromatic and cycloalkyl groups. Hydrogenation conditions…
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▼ The chemical building blocks that comprise petroleum
asphaltenes were determined by cracking samples under conditions
that minimized alterations to aromatic and cycloalkyl groups.
Hydrogenation conditions that used tetralin as hydrogen-donor
solvent, with an iron-based catalyst, allowed asphaltenes from
different geological regions to yield 50-60 wt% of distillates
(<538°C fraction), with coke yields below 10 wt%. Control
experiments with phenanthrene and 5α-cholestane confirmed low
hydrogenation catalytic activity, and preservation of the
cycloalkyl structures. Quantitative recovery of cracking products
and characterization of the distillates, by gas
chromatography-field ionization–time of flight high resolution mass
spectrometry, displayed remarkable similarity in molecular
composition for the different asphaltenes. Paraffins and 1-3 ring
aromatics were the most abundant building blocks. The diversity of
molecules identified, and the high yield of paraffins were
consistent with high heterogeneity and complexity of molecules,
built up by smaller fragments attached to each other by bridges.
The sum of material remaining as vacuum residue and coke was in the
range of 35-45 wt%; this total represents the maximum amount of
large clusters in asphaltenes that could not be converted to
lighter compounds under the evaluated cracking conditions. These
analytical data for Cold Lake asphaltenes were transformed into
probability density functions that described the molecular weight
distributions of the building blocks. These distributions were
input for a Monte Carlo approach that allowed stochastic
construction of asphaltenes and simulation of their cracking
reactions to examine differences in the distributions of products
associated to the molecular topology. The construction algorithm
evidenced that a significant amount of asphaltenes would consist of
3-5 building blocks. The results did not show significant
differences between linear and dendritic molecular architectures,
but suggested that dendritic molecules would experience slower
reaction rates as they required more breakages to reach a given
yield of distillates. Thermal cracking of asphaltenes in heavy oils
and bitumens can dramatically reduce viscosity, enabling pipeline
transportation with less solvent addition. The viscosities of the
products from visbreaking reactions of two different heavy oils
were modeled with lumped kinetics based on boiling point
pseudo-components, and with the estimation of their individual
fluid properties. The model was tuned with experimental viscosity
data, and provided estimations of viscosities at different
temperatures with absolute average deviations lower than
31%.

Rueda-Velasquez, R. I. (2013). Characterization of asphaltene molecular structures by
cracking under hydrogenation conditions and prediction of the
viscosity reduction from visbreaking of heavy oils. (Doctoral Dissertation). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/5m60qs45r

Chicago Manual of Style (16th Edition):

Rueda-Velasquez, Rosa I. “Characterization of asphaltene molecular structures by
cracking under hydrogenation conditions and prediction of the
viscosity reduction from visbreaking of heavy oils.” 2013. Doctoral Dissertation, University of Alberta. Accessed March 21, 2019.
https://era.library.ualberta.ca/files/5m60qs45r.

Rueda-Velasquez RI. Characterization of asphaltene molecular structures by
cracking under hydrogenation conditions and prediction of the
viscosity reduction from visbreaking of heavy oils. [Doctoral Dissertation]. University of Alberta; 2013. Available from: https://era.library.ualberta.ca/files/5m60qs45r

As the need for developing environmentally friendly chemistry continues to become more apparent, catalytic asymmetric hydrogenation has risen to the forefront as a reliable and…
(more)

▼

As the need for developing environmentally friendly chemistry continues to become more apparent, catalytic asymmetric hydrogenation has risen to the forefront as a reliable and eco-friendly method for enantioselective synthesis. We herein describe our progress toward the synthesis of valuable structural motifs via hydrogenation: chiral 1,2-diamines, 1,3-diamines and substituted cyclohexanes.
We propose a strategy whereby protected 1,2-diimine and 1,3-diimine surrogates can be hydrogenated selectively and deprotected to furnish the desired chiral amines. Using this strategy, it was demonstrated that imidazolone precursors could be hydrogenated with >20:1 diastereoselectivity to give latent 1,2-diamines, albeit with no enantiomeric excess.
We further propose that substituted benzene rings linked to an oxazolidinone
chiral-auxiliary can be diastereoselectively hydrogenated using a heterogeneous metal catalyst. Following hydrogenation, the chiral cyclohexanes could be obtained in up to quantitative yield and 99% diastereomeric excess.

► Chapter 1. Overview of Carbon Dioxide Hydrogenation for the Production of Formic Acid As the world’s energy demands increase, our resources dwindle and the need…
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▼ Chapter 1. Overview of Carbon Dioxide Hydrogenation
for the Production of Formic Acid As the world’s energy demands
increase, our resources dwindle and the need for a sustainable
energy source is pertinent. Our current energy infrastructure is
dominated by fossil fuel use. Hydrogen, on the other hand, is
potentially an ideal energy carrier as it is emissions-free when
burned and can be used in fuel cells. Significant advances are
still needed to develop more efficient ways to produce and store
H2. The hydrogenation of CO2 to formic acid and/or methanol
provides an encouraging and reversible approach for a hydrogen
storage material. The first example of homogeneously catalyzed
hydrogenation of carbon dioxide was in 1976. Over the past 40
years, there has been excellent progress in the development of
catalysts for CO2 hydrogenation. Typically, homogenous catalysts
found to be effect are 2nd and 3rd row transition metals of groups
8-10. In recent years, base-metals (common and inexpensive metals)
have demonstrated promising results. This chapter is designed to
highlight important discoveries throughout the history of carbon
dioxide hydrogenation. Chapter 2. Development of a Transition Metal
/ N-Heterocyclic Carbene Cooperative System for the Hydrogenation
of Carbon Dioxide to Formic Acid Over the past few decades, the
conversion of small molecules such as H2, N2, O2, CH4, C2H4, CO,
and CO2 have attracted considerable attention. Many of these
molecules are thermodynamically or kinetically stable and their
usefulness depends on overcoming significant barriers. Frustrated
Lewis pairs and N-heterocyclic carbenes have become common
strategies to activate unreactive small molecule likes CO2 and H2.
However, a hybrid approach utilizing both a transition metal and an
activator has only recently been investigated for the
transformation of small molecules to more useful and complex
compounds. A novel method for these transformations is the use of a
bifunctional catalyst system that incorporates a Lewis basic
N-heterocyclic carbene and a Lewis acidic transition metal. This
chapter highlights our serendipitous discovery that small
quantities of bicarbonate and other inorganic salts enhanced the
productivity of formic acid in CO2 hydrogenation reactions. The
phenomenon was general for many noble-metal catalysts and for one
of the most efficient base-metal hydrogenation catalysts.
Additionally, the synthesis of a transition metal complex bearing a
pendant dihydroimidazolium salt is described. Stoichiometric and
catalytic applications of the newly designed complex were explored
in investigate our Lewis base / transition metal approach to small
molecule activation. Chapter 3. Chemistry of Iron N-Heterocyclic
Carbene Complexes N-heterocyclic carbenes are one of the most
versatile ligands in organometallic chemistry due to their unique
properties as ancillary ligands. Although NHCs are typically potent
σ-donors (a) with minor contributions from π*-backdonation (b),
they also have the ability to accept electron density from the
metal…
Advisors/Committee Members: Jeffery A. Byers (Thesis advisor).

► Increasing energy demands have been met with added combustion of fossil fuels. The massive quantities of carbon dioxide (CO2) given off as a byproduct of…
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▼ Increasing energy demands have been met with added combustion of fossil fuels. The massive quantities of carbon dioxide (CO2) given off as a byproduct of these processes have led to environmental and economical ramifications. Consequently, great emphasis has been placed in remediating CO2 emissions through Carbon Capture and Sequestration (CSS) technologies. A limitation of CSS is that it fails to productively use CO2. A complementary approach is to utilize CO2 as a C-1 source. This dissertation discusses several strategies for the valorization of CO2 to methanol (CH3OH) stemming from fundamental hydrogenation studies.
Chapter 2 outlines a facile approach for the in situ generation of ester hydrogenation catalysts. Unlike traditional methods, this simple approach circumvents the use of sub-stoichiometric alkoxide base. Systematic studies of ligand and base effects on the hydrogenation of the esters, are disclosed. Generally, diphenylphosphinoethylamine, was found to form the most active catalyst for the hydrogenation of alkyl and aryl esters with >80% yield for select substrates. Mechanistic studies elucidated the unproductive, base-catalyzed decarbonylation of the formate ester with traditional alkoxide bases. Consequently, alternatives were investigated and K3PO4 was found to be a viable and compatible substitute.
The improved insight from formate ester hydrogenation guided our studies for the one-pot hydrogenation of CO2 to CH3OH. Application of these catalysts and conditions to the cascade hydrogenation of CO2 identified incompatibility with Lewis acids. Chapter 3 focuses on this limitation and discloses a new class of ester hydrogenation catalysts that are compatible with Lewis acids. Application of these half-sandwich ester hydrogenation catalysts to the Lewis acidic cascade system led up to 8 turnovers of CH3OH in a single-pot batch reactor. Further studies implicate labile ligands as a source of inhibition.
In Chapter 4, a conceptually novel approach is disclosed, wherein CO2 is captured using an amine scrubbing agent (NHMe2) and subsequently hydrogenated in a single pot to >500 turnovers of CH3OH. Up to 96% of CO2 was converted to a mixture of CH3OH and N,N-dimethylformamide (DMF). Mechanistic studies of the pathway identify DMF as a key intermediate. This strategy of carbon capture and hydrogenation provides a complementary approach to many industrial carbon capture methods.
In an effort to develop an earth-abundant process for the hydrogenation of CO2 to CH3OH, iron catalysts were investigated as surrogates to the ruthenium catalysts used in Chapter 4. These iron-catalysts demonstrated high activity for the hydrogenation of amides yielding C–N bond scission products with high selectivity. DMF, a key intermediate in the CO2 to CH3OH pathway developed in Chapter 4, was hydrogenated to yield >1000 turnovers of CH3OH and HNMe2. Kinetic studies were performed to compare the activity of the earth abundant iron catalyst to ruthenium. Remarkably, under otherwise identical conditions, the iron and ruthenium…
Advisors/Committee Members: Sanford, Melanie S (committee member), Thompson, Levi Theodore (committee member), Matzger, Adam J (committee member), Szymczak, Nathaniel (committee member).

► Homogeneous organometallic species serve as useful catalysts for a vast number of chemical transformations. Ancillary ligands which bind to the metal center are employed to…
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▼ Homogeneous organometallic species serve as useful
catalysts for a vast number of chemical transformations. Ancillary
ligands which bind to the metal center are employed to modulate the
reactivity of the metal, and have been key to the discovery and
improvement of most types of transition metal-mediated reactions.
This thesis describes the design and application of P,N-ligands in
platinum group-catalyzed reactions, specifically the Ru- and
Ir-catalyzed ketone transfer hydrogenation (TH) and the
Pd-catalyzed cross-coupling of aryl (pseudo)halides and N-H
containing substrates. A zwitterionic Ru-species featuring a donor
substituted P,N-indenide ligand was found to be an excellent
catalyst for ketone TH, providing turnover frequencies (TOFs) as
high as 300 000 h-1, while related cationic Ru-complexes ligated by
P,N-indene ligands were found to be rather poor catalysts.
Ir-complexes supported by either indene or indenide P,N-ligands
were also found to be active TH catalysts (TOFs ~30 000 h-1),
however phenylene P,N ligands, specifically (o-tBu2P-C6H4)NMe2,
displayed optimal catalytic performance, allowing for rapid ketone
reduction (TOFs of >100 000 h-1), at low catalyst loadings (as
low as 0.004 mol% Ir). Enantioselective TH was achieved by
employing the suitably substituted, commercially available
P,N-ligand, Cy-Mandyphos in combination with [Ir(COD)Cl]2 and
NaPF6. The use of P,N-ligands in Pd-catalyzed C-N cross coupling,
specifically (o-R2P-C6H4)NMe2 (R = tBu or 1-Ad), allowed for the
development of a highly versatile catalyst system for this
reaction. In combination with [Pd(allyl)Cl]2 or [Pd(cinnamyl)Cl]2,
the above described ligands enabled the cross-coupling of aryl and
heteroaryl chlorides and bromides to a diverse range of amine and
related substrates such as primary alkyl- and arylamines, cyclic
and acyclic secondary amines, N-H imines, hydrazones, lithium
amide, and ammonia. Reactions could be performed at low catalyst
loadings (0.5-0.02 mol% Pd) with excellent functional group
tolerance and chemoselectivity. The ligand
N-[2-di(1-adamantylphosphino)phenyl]morpholine in combination with
[Pd(cinnamyl)Cl]2 was found to provide excellent reactivity for the
cross-coupling of ammonia to aryl chlorides with catalyst loadings
of 0.3-5 mol% Pd. Sterically unbiased substrates containing
electron-donating groups were tolerated with minimal competing
diarylation. Aryl tosylates could be coupled with ammonia at room
temperature and chemoselective ammonia arylation in the presence of
other amine functionality was well tolerated. Pd-catalyzed
cross-coupling of hydrazine with aryl chlorides and tosylates was
achieved employing N-[2-di(1-adamantylphosphino)phenyl]-morpholine
as the ligand. Good yields of the desired, mono-functionalized aryl
hydrazine product was observed for a range of substrates at 5 mol%
Pd. Selective hydrazine coupling was observed in the presence of
other NH-functionality and NH-indazoles could be prepared by the
tandem cross-coupling/condensation of hydrazine with
2-chlorobenzaldehydes.
Advisors/Committee Members: Prof. Lutz Ackermann (external-examiner), Prof. Mark Stradiotto (graduate-coordinator), Prof Neil Burford (thesis-reader), Prof. Kevin R. Grundy (thesis-reader), Prof. Alison Thompson (thesis-reader), Prof. Mark Stradiotto (thesis-supervisor), Not Applicable (ethics-approval), Not Applicable (manuscripts), Not Applicable (copyright-release).

► The Noyori-type catalyst trans-[Ru((R)-BINAP)(H)2((R,R)-dpen)] (6) and its analogues are among the most active and enantioselective ketone hydrogenation systems reported to date. Its applications towards other…
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▼ The Noyori-type catalyst
trans-[Ru((R)-BINAP)(H)2((R,R)-dpen)] (6) and its analogues are
among the most active and enantioselective ketone hydrogenation
systems reported to date. Its applications towards other types of
carbonyl compounds are, however, understudied. This dissertation
describes the first applications of this catalyst system towards
hydrogenations of esters and imides under mild reaction conditions.
Further, a detailed mechanistic study of this system is presented
using ketones, esters, and imides as substrates. The dihydride 6
was highly active towards the hydrogenation of esters.
Stoichiometric reactions between 6 and lactones proceeded at –80 °C
to form the net hydride insertion products, Ru-hemiacetaloxides.
The hemiacetaloxides were further hydrogenated at –40 °C under ~2
atm of H2 to form the corresponding Ru-alkoxides. Catalytic
hydrogenations could be carried out, even at –20 °C under 4 atm of
H2, however, these hydrogenations slowed over time due to
deactivation of the catalyst by primary alcohol products. The first
homogeneous monohydrogenation of imides was developed using 6 and
related compounds as catalysts. Further, upon optimization of
reaction conditions and imide structure, meso-cyclic imides were
desymmetrized in high ee via the monohydrogenation to form
kinetically unfavoured trans-hydroxy lactams with up to 5
stereogenic centres. Furthermore, the number of stereogenic centres
was increased from 5 to 7 using N-acyliminium ion chemistry. A
model for the origin of enantioselection was proposed using
substrate-catalyst steric interactions. Low temperature NMR studies
revealed that base catalyzes the rapid cis-trans isomerization to
form the thermodynamically more stable trans-isomer. It was
proposed that this rapid isomerization prevents racemization of a
product. Transition states for the formation of Ru-alkoxides from
addition between 6 and acetophenone were studied using an
intramolecular trapping experiment. Addition between 6 and
4-hydroxymethylacetophenone at –80 °C exclusively formed the net
hydride insertion product, Ru-secondary-alkoxide. Combined with
controlled experiments, this result is strong evidence for the
formation of a Ru–O interaction in the transition state, which
supports concerted formation of the Ru-alkoxides from 6 and
acetophenone.

▼ Large polycyclic aromatic nitrogen containing
asphaltene model compounds, with molecular weights from 535 to 702
g/mol, were catalytically hydrogenated and hydrodenitrogenated in
the presence of a commercial NiMo/γAl2O3 catalyst in a stainless
steel batch reactor at 370 °C and 17.9 MPa total pressure for 1 h.
The patterns and pathways of hydrogenation of two families of model
compounds were investigated: alkyl-bridged pyrenes linked to a
pyridine centre ring and substituted cholestane – benzoquinoline
compounds. Analysis of reaction products by matrix assisted laser
desorption ionization – mass spectrometry, high performance liquid
chromatography, and gas chromatography demonstrated that for the
pyrene/pyridine family there was a strong preference for
hydrogenation of the bridged pyrene groups compared to the centre
pyridinic ring. For the cholestane family, no cracking or
hydrodenitrogenation reactions occurred. Results imply that
hydrotreatment of similar large nitrogen asphaltene compounds are
dominated by reactions other than
hydrodenitrogenation.

▼ Prior mechanistic studies demonstrate that
trans-[RuH2((R)-BINAP)((R,R)-dpen)] is a remarkably active carbonyl
reducing agent at low-temperatures in THF-d8. This dissertation
describes the monohydrogenation of cyclic meso-imides using this
catalyst and related complexes under mild conditions. Bicyclic
meso-imides were chemo-, diastereo- and enantio-selectively
desymmetrized to form chiral hydroxy lactams (90-99% conversion,
88-97% ee, dr >93:7, C=O/C=C selectivity >99%) with
up to five stereogenic centers in one hydrogenation under the
reported reaction conditions (0.1-1 mol% Ru, 0.9-9.9 mol% KOt-Bu
under 50 atm H2 at 0-22 °C in 3-57 h). Compounds of academic and
commercial interest were also synthesized from these hydroxy
lactams. A detailed low-temperature investigation into the
desymmetrization-hydrogenation reaction led to the discovery of a
previously unobserved active pathway for carbonyl hydrogenation.
Reaction intermediates resulting from the unexpected deprotonation
and di-deprotonation respectively of the parent dihydrides i.e.
trans-M[RuH2((R,R)-HN–CH(Ph)CH(Ph)NH2)((R)-BINAP)], where M = K+ or
Li+, and trans-M2[RuH2((R,R)-HN–CH(Ph)CH(Ph)N–H)((R)-BINAP)] where
M = Li+, were synthesized and characterized. The mono-deprotonated
dihydrides were found to have unprecedented activity towards the
hydrogenation of imide and amide carbonyls at low temperatures in
THF-d8. The origins of the enantioselection for this reaction were
also proposed using simple well-defined models based on current
literature and the outcomes of this investigation. The
hydrogenation of amides using trans-[RuH2((R)-BINAP)((R,R)-dpen)]
and its variants is also described herein. In contrast to the high
activity of trans-[RuH2((R)-BINAP)((R,R)-dpen)] towards ketones,
imides (in the presence of base), and esters, the catalyst
exhibited low to moderate activity towards amides. This difference
in activity was attributed to thermal instability of the catalyst
at high temperatures. By tethering the phosphine and amine units
together, a robust pre-catalyst, [Ru(η3-C3H5)(Ph2P(CH2)2NH2)2]BF4
was prepared, which, when combined with NaOMe (Ru:NaOMe:Amide =
1:500:10,000), catalyzes the hydrogenation of amides with a TON up
to 7120. The analogous base-free system comprising
[Ru(η3-C3H5)(Ph2P(CH2)2NH2)2]BF4 and NaBH4 was also shown to be an
efficient catalyst system for this reaction under reported
conditions (0.1 mol% Ru, 0.2 mol% NaBH4 under 50 atm H2 at 100 °C
in 24 h) in contrast to
trans-[RuH(η1-BH4)((R)-BINAP)((R,R)-dpen)].

John, J. M. (2013). Design, Development and Mechanistic Study of Ruthenium-Based
Catalysts for the Hydrogenation of Imides and Amides. (Doctoral Dissertation). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/v692t638s

Chicago Manual of Style (16th Edition):

John, Jeremy Michael. “Design, Development and Mechanistic Study of Ruthenium-Based
Catalysts for the Hydrogenation of Imides and Amides.” 2013. Doctoral Dissertation, University of Alberta. Accessed March 21, 2019.
https://era.library.ualberta.ca/files/v692t638s.

MLA Handbook (7th Edition):

John, Jeremy Michael. “Design, Development and Mechanistic Study of Ruthenium-Based
Catalysts for the Hydrogenation of Imides and Amides.” 2013. Web. 21 Mar 2019.

Vancouver:

John JM. Design, Development and Mechanistic Study of Ruthenium-Based
Catalysts for the Hydrogenation of Imides and Amides. [Internet] [Doctoral dissertation]. University of Alberta; 2013. [cited 2019 Mar 21].
Available from: https://era.library.ualberta.ca/files/v692t638s.

Council of Science Editors:

John JM. Design, Development and Mechanistic Study of Ruthenium-Based
Catalysts for the Hydrogenation of Imides and Amides. [Doctoral Dissertation]. University of Alberta; 2013. Available from: https://era.library.ualberta.ca/files/v692t638s

► The synthesis of a family of para-substituted pyridine di(imine) ligands, and their corresponding iron dihalide, dicarbonyl and dinitrogen complexes are described. The influence of the…
(more)

▼ The synthesis of a family of para-substituted pyridine di(imine) ligands, and their corresponding iron dihalide, dicarbonyl and dinitrogen complexes are described. The influence of the substituents on the electronic structure of each derivative was investigated using a combination of X-ray diffraction, cyclic voltammetry, infrared, Mößbauer, and NMR spectroscopies as well as density functional theory. No dramatic changes to the electronic structure description were observed as a result of the para-substituent. However, significant differences in catalytic activity were observed for the hydrogenation of olefins and the [2[pi] + 2[pi]] cycloaddition of [alpha],[omega]-heptadienes, and were also found to be substrate dependent. The electronic structure and catalytic activity of a structurally related pyridine di(carbene) complex, (iPrCNC)Fe(N2)2 was investigated. The spectroscopic data establish that (iPrCNC)Fe(N2)2 and several of its derivatives are redox non-innocent. They are best described as hybrid structures with [(iPrCNC0)Fe0] and [(iPrCNC2-)FeII] resonance forms with the iPrCNC ligand acting as a [pi]-acceptor. The activity of (iPrCNC)Fe(N2)2 for the catalytic hydrogenation of olefins and [2[pi] + 2[pi]] cyclization of [alpha],[omega]-diolefins was also investigated. (iPrCNC)Fe(N2)2 exhibited hydrogenation activities that were consistent with the trends observed in pyridine di(imine) iron olefin hydrogenation, but exhibited no activity for the [2[pi] + 2[pi]] cycloaddition of [alpha],[omega]-heptadienes. Isotopic experiments indicated that a competitive, unproductive 2,1-insertion pathway or a vinylic C-H activation mechanism was responsible for the deviation in hydrogenation activity trends observed with 1,1-diphenylethylene and the electron-rich iron catalysts. A series of dialkyl dinitrogen complexes were prepared from treatment of (iPrCNC)FeBr2 with two equivalents of the corresponding alkyl lithium reagent. The iron dialkyl dinitrogen complexes were characterized by infrared, NMR and Mößbauer spectroscopies as low-spin, ferrous compounds. One member of the series, (iPrCNC)Fe(CH3)2(N2) underwent extrusion of ethane at 23 [MASCULINE ORDINAL INDICATOR]C. The mechanism of this transformation was investigated by isotopic cross-over experiments. The dimeric iron bis(dinitrogen) complex, [(MeBPDI)Fe(N2)]2([MICRO SIGN]2-N2) was prepared by sodium naphthalenide reduction of the corresponding iron dichloride. This complex was established to be more susceptible to contamination by THF complexes, and underwent the irreversible formation of [eta]6-arene species in solution. [(MeBPDI)Fe(N2)]2([MICRO SIGN]2-N2) and (iPrBPDI)Fe(N2)2 exhibited remarkably lower activity for the hydrogenation of ethyl 3,3dimethylacrylate relative to (iPrPDI)Fe(N2)2. NMR studies and stoichiometric experiments established that this was due to the more electrophilic iron center as engendered by the BPDI chelate, resulting in a greater affinity for carbonyl coordination. A family of bis(oxazoline) iron dialkyl complexes were prepared by…
Advisors/Committee Members: Ganem, Bruce (committeeMember), Wolczanski, Peter Thomas (committeeMember).

►Hydrogenation of CO2 to formic acid is usually performed with precious metal catalysts. However, due to the cost and scarcity of precious metals, recent research…
(more)

▼Hydrogenation of CO2 to formic acid is usually performed with precious metal catalysts. However, due to the cost and scarcity of precious metals, recent research has focused instead on first row transition metals. Of specific interest to our group are bis-phosphine and carbene complexes of iron, cobalt and nickel. Initial efforts found catalytically active species, which generated decent turn over numbers (TON). It was found that 10 different metals have at least some catalytic activity for this reaction, when combined with 1,2-bis(dimethylphosphino)ethane, including Fe, Co, Ni, In, Zn and Mo. The most active was an iron complex that had a TON of 726, High pressure NMR spectra obtained throughout the course of the reaction provide insight by which FeCl2(dmpe)2 hydrogenates CO2 to formic acid.
As part of a search for CO2 hydrogenation catalysts base upon abundant metals efficient catalysts with carbene ligands were also found. The combination of either FeCl2, Ni(OAc)2, CoCl2 and Co(OAc)2 with various carbene or carbene precursors from catalysts in situ capable of hydrogenating CO2 to formic acid with TONs of up to 420.

► Catalytic asymmetric synthesis is a significant component in modern organic chemistry. Transition metal enantioselective catalysis is certainly among the most challenging and widely investigated areas…
(more)

▼ Catalytic asymmetric synthesis is a significant
component in modern organic chemistry. Transition metal
enantioselective catalysis is certainly among the most challenging
and widely investigated areas in organometallic chemistry. The
design and synthesis of efficient chiral phosphorus ligands and the
exploration of their applications in transition metal-catalyzed
asymmetric hydrogenations are the main focus of this dissertation.
By introducing a bridge with variable length to link the chiral
atropisomeric biaryl groups, a novel class of conformationally
rigid Cn-TunePhos (n = 1-6) ligands was designed and synthesized in
three different routes. The additional non-chiral linkage not only
minimizes the conformational rotation but also defines the dihedral
angle and the bite angle with improved precision. This family of
TunePhos ligands has proven highly efficient in a variety of
asymmetric hydrogenations. Ru/Cn-TunePhos catalyzed asymmetric
hydrogenation of allyl phthalimides provided an efficient method
for the synthesis of ¦Â-methyl chiral amines. A series of
C3-TunePhos derivatives with different steric and electronic
properties was prepared by atropdiastereoselective Ullmann coupling
reaction of the biaryl diethyl phosphonate. The procedure is
featured by highly efficient central-to-axial chirality transfer
with diastereomeric excess > 99%. Enantiomerically pure Ru
complexes containing these ligands have been prepared and applied
to the catalytic enantioselective hydrogenation of ¦Â-keto esters.
An excellent level of enantioselection (up to 99.5% ee) has been
attained. A pair of bisphosphine ligands containing double hybrid
chiral axials in a six-carbon bridging unit were designed and
synthesized. The presence of chiral binaphthyl auxiliary together
with another chiral biphenyl phosphine moiety offers the
opportunity to prepare diastereomeric ligands. The matching and
mismatching effects caused by interactions between the two
stereochemical elements within each ligand displayed dramatic
difference in asymmetric hydrogenation of ¦Á-keto esters. An
efficient Rh-bisphospholane catalyzed highly enantioselective
synthesis of 3-arylbutanoic acids was explored with several
remarkable features: 1) Up to 99% ee values and 5,000 turnover
numbers can be achieved; 2) cooperation of highly rigid
electron-donating P-chiral bisphospholane DuanPhos ligand with
optimal solvent and additive is the key to efficient
transformations; 3) the simplicity of obtaining substrates and
highly enantioselective hydrogenation under mild conditions make
this approach more attractive and practical.

► This thesis summarizes the author’s graduate research on catalytic asymmetric hydrogenation at Penn State. The first chapter gives a brief review of ligand development in…
(more)

▼ This thesis summarizes the author’s graduate research
on catalytic asymmetric hydrogenation at Penn State. The first
chapter gives a brief review of ligand development in asymmetric
hydrogenation, with a focus on the long-term effort of the Zhang
group in this area. Several important factors for ligand design are
discussed, including steric hindrance, electronic control, and
practical considerations. Chapter 2 delineates the development of a
novel triphosphorus bidentate phosphine-phosphoramidite ligand with
pseudo C2-symmetry, from initial design, through ligand synthesis
and characterization, to its application in asymmetric
hydrogenation. A major success of this ligand is highlighted in
asymmetric hydrogenation of ortho substituted á-arylenamides with
excellent enantioselectivity (up to 99.6% ee), which had not been
possible prior to this work. In Chapter 3, the development of
conformationally rigid spirocyclic monodentate phosphoramidite
ligands is discussed. A highly efficient, large-scale route for the
synthesis of chiral spirocyclic diol is presented, followed by the
discovery of an interesting acid-mediated rearrangement of
spirocyclic backbones. These spirocyclic ligands are applied in
highly enantioselective catalytic asymmetric hydrogenation and
asymmetric conjugate addition reactions.

► This dissertation focuses on fundamental understanding of the roles of supports and noble metals in the sulfur-tolerant catalysts for low-temperature hydrogenation of aromatics in the…
(more)

▼ This dissertation focuses on fundamental understanding
of the roles of supports and noble metals in the sulfur-tolerant
catalysts for low-temperature hydrogenation of aromatics in the
presence of sulfur. Emphasis was placed on investigating the effect
of supports and supported metals for high sulfur tolerance and
verifying a catalyst design concept for the sulfur-tolerant noble
metal catalyst based on shape selective exclusion of sulfur and
hydrogen spillover for low- temperature hydrogenation of aromatics
[C.S. Song, Chemtech, 29 (1999) 26-30]. The hybrid
zeolite-supported Pd catalyst was prepared to improve sulfur
tolerance, based on the proposed catalyst design concept. The
hybrid catalyst consists of Pd supported on Y and A type zeolites.
For further investigation on small pore system in hybrid catalyst,
surface metal passivation by silica coating and pore size control
by potassium ion exchange were employed to zeolite A-supported Pd
catalyst. Although Pd on Zeolite A showed no catalytic activity for
hydrogenation of tetralin, adding the small-pore catalyst to Pd/Y
significantly enhanced sulfur tolerance of the catalyst for both
naphthalene and tetralin hydrogenation in the presence of sulfur in
the form of benzothiophene. Sulfur tolerance of the hybrid catalyst
is mainly attributed to the small pore system, inducing
size-selective exclusion of bulky sulfur compounds as well as
hydrogen spillover from metal inside small pore component. Hydrogen
spillover plays two roles in maintaining high sulfur tolerance of
the hybrid catalyst: first, regeneration of sulfur-poisoned metal
active sites in the large pores of Pd/Y as well as
hydrodesulfurization of aromatic sulfur compounds over the zeolite
Y support. On the basis of the above results and discussion
focusing on the importance of the supports and metal types for
improving sulfur tolerance, the hybrid catalyst system based on the
new design concept of sulfur tolerant catalyst is effective in the
development of sulfur tolerant catalysts for low-temperature
hydrogenation of aromatics.

► Asymmetric hydroformylation is one of the most challenging transformations because it requires both high enantioselectivities and regioselectivies with high activity. Also, there are few effective…
(more)

▼ Asymmetric hydroformylation is one of the most
challenging transformations because it requires both high
enantioselectivities and regioselectivies with high activity. Also,
there are few effective ways to prepare chiral ligands. To address
these challenges, a series of new diphosphite ligands have been
developed in our lab. These new ligands have been investigated in
rhodium-catalyzed asymmetric hydroformylation of vinyl acetate and
its derivatives. They provide moderate enantioselectivities (up to
80 % ee) and excellent regioselectivies (b/l up to 98/2) in
rhodium-catalyzed asymmetric hydroformylations of vinyl acetate and
its derivatives. Although numerous efficient chiral ligands have
been developed for asymmetric hydrogenation, there is no universal
ligand which can be applied in all prochiral substrates with high
enantioselectivity. To expand the substrate scope, the development
of new chiral ligands is highly desirable. A chiral diphosphine
ligand has been designed and synthesized. This new ligand bearing
chiral C3-biphenyl backbone provides excellent enantioselectivies
in rhodium-catalyzed asymmetric hydrogenation of á-dehydroamino
acid esters and itaconate.

► Tall oil is a byproduct of the standard wood pulping process in the paper industry. It is primarily made up of C:18 fatty acids, rosin…
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▼ Tall oil is a byproduct of the standard wood pulping process in the paper industry. It is primarily made up of C:18 fatty acids, rosin acids and a minor fraction of neutrals. Normally, tall oil is further distilled into fractions and then hydrogenated or dehydrogenated into different products. In this project, three heterogeneous catalytic methods of producing byproducts of various distilled tall oil fractions were examined at lower temperatures and pressures than the industry norm in an attempt to develop cheaper production processes. Reactions were conducted in stirred batch reactors of different sizes and product compositions were analyzed primarily by GC/MS and GC. The selective hydrogenation of abietic acid, a common rosin acid, to abietyl alcohol in the presence of fatty acids was examined first. For the conditions and catalysts used, the yield to abietyl alcohol was small and the reaction was not selective, giving both ring hydrogenation and dehydrogenation. Second, the dehydrogenation of abietic acid to dehydroabietic acid in a primarily rosin feed was studied. The Pd/C class of catalysts had the greatest activity. There was a maximum yield of 58% associated with equilibrium, and the reaction took place predominantly as a disproportionation. The reaction was very slow at temperatures less than 230 °C, and decarboxylation occurred in greater abundance as time or temperature of the reaction was increased. In the mainly rosin feed (HYR), some polymerization occurred; however, the amount of polymer was relatively small, the polymer was thermally labile and most likely thermal in origin. Finally, the gas environment (H2, N2, air) did not have a significant effect on the reaction. The final reaction studied was the selective hydrogenation of unsaturated fatty acids to unsaturated fatty alcohols in a mainly fatty acid feed. The results showed that the hydrogenation could not occur to a significant degree at conditions less than 250 °C and 87 bar, for any of the common classes of hydrogenation catalysts.

▼ Chapter 1: The syntheses of neutral (halide and aryl) and cationic vanadium bisimides are described. Characterization of the complexes by X-ray diffraction, 13C NMR, 51V NMR, and V L2,3-edge NEXFAS provide a description of the electronic structure in comparison to group 6 bisimides and the bent metallocene isolobal analogs.Chapter 2: Under 1 atm of H2, [V(NtBu)2(PMe3)3][Al(PFTB)4], 1.10, (PFTB = perfluoro-tert-butoxide), was shown to catalytically semihydrogenate alkynes to (z)- alkenes. Synthetic and DFT studies, in combination with H2/D2 crossover and PHIP NMR experiments, indicate that H2 is activated by [1,2]-addition to 1.10 and upon the insertion of alkyne into the V-H bond of the vanadium hydrido amide A, the product alkene and 1.10 are generated by the [1,2]-α-NH-elimination of the alkenyl ligand.Chapter 3: A series of carbon monoxide, isocyanide, and nitrile complexes of [V(PR3)2(NtBu)2][Al(PFTB)4], (R = Me, Et) were prepared. [V(PMe3)3(NtBu)2][Al(PFTB)4], (PFTB = perfluoro-tert-butoxide) reacts with 2,6- xylylisocyanide (CNXyl) or acetonitrile to afford complexes 3.1 and 3.2. Complex 3.1 was crystallographically characterized revealing a C-N bond length of (1.152(4) Å), and IR studies showed a C-N stretching frequency of 2164 cm-1. Treatment of [V(PEt3)2(NtBu)2][Al(PFTB)4] with CNXyl yielded the desired isocyanide complex in 60% yield with a C-N stretching frequency of 2156 cm-1. The desired d0 vanadium bisimido, carbonyl complex was achieved via the exposure of 1.11 to 1 atm of CO. Complex 3.4 has a C-O stretching frequency of 2015 cm-1 (CaF2 solution cell). Isotopic labeling with 13CO reveals a stretching frequency of 1970 cm-1, which confirms the assignment of the complex as a terminal η1-CO complex and which is also implied by its NMR data in comparison to the other crystallographically characterized compounds presented here. The 13C{31P}{1H} NMR spectrum of 3.4-13C reveals a broad singlet at 228.36 ppm implying deshielding of the carbonyl carbon. This datum, in conjunction with the shielded vanadium NMR shift of -843.71 ppm, suggests π back-bonding is operative in the bond between carbon monoxide and 1.11. This model was further confirmed by DFT analysis of the model complex [V(η1-CO)(PMe3)2(NtBu)2]+, 3.5, which reveals that the basis of the reduced stretching frequency in 3.4 is π back-bonding from the 2b1 and 1b2 orbitals of 1.11.

Note: this citation may be lacking information needed for this citation format:Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

La Pierre HS. Neutral and Cationic Vanadium Bisimido Complexes: Their Synthesis, Characterization, and Application in the Binding, Activation, and Catalytic Functionalization of Small Molecules. [Thesis]. University of California – Berkeley; 2011. Available from: http://www.escholarship.org/uc/item/0sx8j7g5

Note: this citation may be lacking information needed for this citation format:Not specified: Masters Thesis or Doctoral Dissertation

Montana State University

27.
Ryffel, James R.
Reaction kinetics of the destructive catalytic hydrogenation of quinoline.

► This thesis focuses on the understanding the effect of various factors, such as physical structures of metal particles, chemical composition of supports and metal-support interactions,…
(more)

▼ This thesis focuses on the understanding the effect of various factors, such as physical structures of metal particles, chemical composition of supports and metal-support interactions, on the catalytic performance of Pd or Pt nanocatalysts for hydrodeoxygenation (HDO) of bio-oil model compounds.
The first part of the thesis addressed the alternative catalyst synthesis strategy based on emerging double-flame spray pyrolysis method (FSP), which was able to tune the catalytic properties of nanocatalysts without changing their precursors and chemical compositions during the synthesis. A series of Pd catalysts on the silica-alumina supports, SiO2- , and Al2O3 supports have been synthesized with the tunable surface properties within micro-seconds. The characterization results showed that various flow rates of precursors and gases used for the synthesis of catalysts influenced the formation of the catalyst structures and further change the surface acidity of catalysts due to the correlation between acidity and structure, but, the flow rates did not influence the electronic properties of Pd particles. Therefore, the higher conversion but the similar chemoselectivity have been reached in the hydrogenation of the bio-oil model ketone compound-acetophenone
The second part is to identify the dominant effects from size of metal catalysts (under uniform shape and face) or the support acidity in the hydrodeoxygenation of the bio-oil model compounds of acetophenone, benzaldehyde, and butyrophenone. The uniform cubic Pd particles with different size (8, 13, and 21 nm) have been synthesized and loaded on the most popular supports (SiO2-, Al2O3-, and silica-alumina) with various functional groups and acidity. The results showed different acidities on the supports (Brønsted acidic site for Silica-alumina, Lewis acidic site for Al2O3-, and non/weak silanol OH group for SiO2- support) could not influence the chemoselectivity of the reaction but effected the conversion obviously. The particle size has more significant influence than the acidity. The smallest (8nm) Pd particle catalysts regardless of kinds of supports revealed the highest conversion for the hydrogenation the bio-oil model compounds.
The third part focused on the influence of various types of catalysts with different acidities, chemical composition, and metal-support interaction on enantioselective hydrogenation of several model compounds in two reaction systems: 1). Pt-cinchrona modified system, and 2). Pd-(S) proline modified system. The result indicated acidic supports promoted the both conversion and enantioselectivity. Specially, Pd/SA made by double-FSP method, which has the highest Brønsted acid sites, showed 100 % conversion of isopherone on 60 min with 99% ee values.

► Kinetic studies of a number of interesting and significant reactions involving reaction of molecular hydrogen, olefins and carbon monoxide with solutions of ruthenium chloride complexes…
(more)

▼ Kinetic studies of a number of interesting and significant reactions involving reaction of molecular hydrogen, olefins and carbon monoxide with solutions of ruthenium chloride complexes are described.
Ruthenium trichloride trihydrate, "RuCl₃.3H₀0", which is a mixture of ruthenium(III) and ruthenium(IV), was found to react with molecular hydrogen in dimethylacetamide (DMA) solution under mild conditions, to produce ruthenium(II) and ruthenium(I) in successive steps involving activation of the hydrogen by ruthenium(III) and ruthenium(II): [forumulae omitted]
In aqueous acid solution, the reverse of reaction (1) prevents reduction of ruthenium(III); in DMA, a more basic solvent, the released proton is stabilized and reduction is observed all the way to the univalent state. Convincing evidence was found for the existence of ruthenium(I) in DMA, although no well-characterized ruthenium(I) solid complexes were isolated. The present studies are the first reported on the solution chemistry of ruthenium(I) chlorides.
Ruthenium(I) chloride complexes in DMA (80°) were found to activate molecular hydrogen through dihydride formation for the catalyzed reduction of olefins. The following mechanism is indicated: [formulae omitted]
Accompanying olefin isomerization and some deuterium isotope studies suggest that reaction (5) goes through an ϭ-alkyl hydride intermediate, the hydrogen transfer process involving two consecutive single hydrogen atom transfers to a coordinated olefin. Addition of triphenylphosphine (PPh₃) to the ruthenium(I) catalyst solution decreases the hydrogenation rate. However, reaction of hydrogen with a ruthenium(I) solution containing
PPh₃ and no substrate gave evidence for the formation of a hydride species.
In the presence of PPh₃, reaction of H₂ with ruthenium(II) chloride in DMA does not produce ruthenium(I). The ruthenium(II) hydride intermediate is stabilized by the phosphine ligand yielding the well-known complex RuHCl(PPh₃)₃ which has been found to be extremely active in catalyzing the hydrogenation of olefins. An extremely simple method for the preparation of the catalyst "in situ" is demonstrated, again utilising the basic properties of DMA. A mechanism involving a predissociation of the catalyst, and formation of an ϭ-alkyl intermediate is thought to be operative in the catalyzed hydrogenation of olefins: [formulae omitted]
Both ruthenium(I) and ruthenium(II) chlorides in DMA were
found to absorb carbon monoxide readily at ambient temperatures,
producing Ru[superscript I](CO) and Ru[superscript I](CO)₂, and Ru[superscript II](CO) and Ru[superscript II](CO)₂respectively.
The introduction of carbonyl groups into these ruthenium complexes was
found to inhibit catalytic activity for the hydrogenation of olefins.
The anion [RuCI₄(bipyridine)]²⁻ , in 3 M HC1, was found to be a hydrogenation catalyst for olefin reduction, though not a very efficient one. A mechanism similar to the RuHCl(PPh₃)₃ catalyzed system seems to be involved, and is quite different to that reported for a corresponding…

Hui, B. C. (1969). Activation of molecular hydrogen in solution by complexes of univalent, divalent, and trivalent ruthenium
. (Thesis). University of British Columbia. Retrieved from http://hdl.handle.net/2429/35501

Note: this citation may be lacking information needed for this citation format:Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Hui, Benjamin Ching-Yue. “Activation of molecular hydrogen in solution by complexes of univalent, divalent, and trivalent ruthenium
.” 1969. Thesis, University of British Columbia. Accessed March 21, 2019.
http://hdl.handle.net/2429/35501.

Note: this citation may be lacking information needed for this citation format:Not specified: Masters Thesis or Doctoral Dissertation

Note: this citation may be lacking information needed for this citation format:Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Hui BC. Activation of molecular hydrogen in solution by complexes of univalent, divalent, and trivalent ruthenium
. [Thesis]. University of British Columbia; 1969. Available from: http://hdl.handle.net/2429/35501

Note: this citation may be lacking information needed for this citation format:Not specified: Masters Thesis or Doctoral Dissertation